OpenVPN No server certificate verification method has been enabled

I'm using a R7000 running V1.0.9.28_10.2.32.

I just enabled VPN and tried to connect via a Windows 10 OpenVPN client but get the following errors in the VPN Windows Log

I removed the normal messages at the start of the log but can provide them if required.

Wed May 02 17:00:46 2018 us=65248 WARNING: No server certificate verification method has been enabled. See http://openvpn.net/howto.html#mitm for more info.
Wed May 02 17:00:46 2018 us=65248 OpenSSL: error:140AB18ESmiley FrustratedSL routinesSmiley FrustratedSL_CTX_use_certificate:ca md too weak
Wed May 02 17:00:46 2018 us=65248 MANAGEMENT: Client disconnected
Wed May 02 17:00:46 2018 us=65248 Cannot load certificate file client.crt
Wed May 02 17:00:46 2018 us=65248 Exiting due to fatal error
This is using the downloaded configuration from my Netgear router's Advanced Setup VPN.

I use a static IP provided by my ISP so don't need to provide a a Dynamic DNS setting. I've modified the client1 config accordingly with my external static IP